Prepolymeric (meth) acrylates with polycyclic or aromatic segments

ABSTRACT

The invention relates to monomers according to the formulae  
                 
 
     as well as curable materials containing these monomers.

[0001] The invention relates to multifunctional (meth)acrylates withpolycyclic or aromatic segments as well as materials prepared from them,in particular dental materials.

[0002] The aesthetic aspect in restorative dentistry is becomingincreasingly important. In the anterior tooth area in particular, thepatient can no longer be expected to receive a restoration which doesnot correspond to the natural tooth. The key to the aesthetic aspect isthe opacity of the restoration material.

[0003] By restoration materials is meant within the meaning of thisapplication in particular tooth filling materials, stump build-upmaterials, dental cements, dental varnishes as well as dental materials,such as veneering materials.

[0004] Dental restoration materials are based on curable monomers ormonomer mixtures. Predominantly used in the state of the art areshort-chained monomers based on (meth)acrylates, which lead to a notinconsiderable health risk through the release of non-polymerizedresidual monomers from the restoration material. There has thereforebeen no lack of attempts to switch to other monomer systems.

[0005] Thus for example the application DE-198 60 364 describes curablemonomers based on cyclic siloxane (meth)acrylates. These arecharacterized by a high (meth)acrylate functionality which, in the caseof curable materials prepared from same, leads to good physicalproperties.

[0006] Within the framework of the application DE-198 60 361, cyclicsol-gel-condensable siloxanes are described which, in curable materialsprepared from same, lead to a low polymerization shrinkage and improvedphysical properties.

[0007] Overall, in the state of the art there is no lack ofpolymerizable materials which are characterized by low shrinkage andimproved physical values; however, there is indeed a lack of curablematerials which have improved aesthetic properties, in particular anopacity which guarantees the visual impression of natural toothsubstance.

[0008] The object of the present application is to provide monomers withhigh molecular weight that allow the formulation of dental materialswhich in the cured state have a low opacity in order to guarantee thevisual impression of natural tooth substance.

[0009] This object is achieved by the monomers according to theinvention and the materials formulated from same, according to theclaims.

[0010] An advantage of the monomers according to the invention, inaddition to the fact that they have a high molecular weight, for exampleover 600 g/mol, preferably over 800 g/mol, is also a high (meth)acrylatefunctionality, for example over 2, preferably over 3 in the case ofsurprisingly low viscosity. They are therefore extremely well suited forthe formulation of easily applicable materials. The molecular weight ofthe monomers according to the invention can be so high until the limitof flowability is reached at 23° C.

[0011] The materials formulated from the monomers have a lowpolymerization shrinkage and very high mechanical strength. It istherefore also possible to formulate materials without using customarylow-functional monomers based on pure (meth)acrylate, which for examplereduces the risk to the patient caused by emerging residual monomers.

[0012] The materials formulated from the monomers have in particular anopacity of 80 to 90%, preferably 83 to 87%.

[0013] Furthermore, it is advantageous and surprising that the monomersare storage-stable despite their high number of acrylate or methacrylategroups per molecule.

[0014] The monomers according to the invention have the general formulae(1) or (2), the covalent bonding of a radical E to a siloxane backbonebeing common to the formulae.

[0015] in which the following mean:

[0016] n=an integer from 0 to 10, preferably 1 to 5;

[0017] A=H or linear or branched C₁ to C₁₅ alk(en)yl, preferably methyl,ethyl, propyl, butyl, vinyl, ethinyl, allyl, or C₃ to C₁₅cycloalk(en)yl, preferably cyclopentyl, cyclohexyl, cyclopentadienyl,cyclohexenyl, or C₆ to C₁₂ aryl, preferably phenyl, tolyl, xylyl, orC₈-C₁₈ alkaryl, preferably phenylethylenyl, of the named radicals, oneor more C atoms in each case being able to be replaced by O, C═O,O(C═O), SiR₂ and/or NR, R being an aliphatic radical with 1 to 7 Catoms, in which one or more C atoms can be replaced by O, C═O and/orO(C═O);

[0018] D=E or a hydrocarbon structure which links 2 to 10, preferably 2to 5 cyclosiloxane radicals, the structure being linear or branched orcyclic or polycyclic and containing 2 to 50, preferably 2 to 30 C atomsand additionally 0 to 30, preferably 0 to 20 other atoms from the groupO, N, S, P, Cl, F, Br, I and to which 1 to 9, preferably 1 to 4 of theabove-defined cyclosiloxane radicals according to formula (1), excludingD, are attached. Preferred radicals D are: di(prop-3-yl)ether,di(prop-3-yl)sulphide, di(prop-3-yl)amine, di(prop-3-yl)methylamine,tri(prop-3-yl)amine, di(prop-3-yl)urea, di(prop-3-yl)carbonate, ethyleneglycol di(prop-3-yl)carbonate, diethylene glycol di(prop-3-yl)carbonate,ethylene glycol di(prop-3-yl)ether, diethylene glycoldi(prop-3-yl)ether, 1,2-propanediol di(prop-3-yl)ether, 1,3-propanedioldi(prop-3-yl)ether, 1,3-butanediol di(prop-3-yl)ether, 1,4-butanedioldi(prop-3-yl)ether, 1,4-butenediol di(prop-3-yl)ether, 1,4-butinedioldi(prop-3-yl)ether, 1,5-pentanediol di(prop-3-yl)ether, 1,6-hexanedioldi(prop-3-yl)ether, 1,8-octanediol di(prop-3-yl)ether, 1,9-nonanedioldi(prop-3-yl)ether, 1,10-decanediol di(prop-3-yl)ether,1,12-dodecanediol di(prop-3-yl)ether, oxalic acid di(prop-3-yl)ester,malonic acid di(prop-3-yl)ester, succinic acid di(prop-3-yl)ester,adipinic acid di(prop-3-yl)ether, sebacic acid di(prop-3-yl)ether,1,2-ethanediyl, 1,4-pentadienyl, 1,5-pentanediyl, 1,5-hexadienyl,1,6-heptadienyl, 1,7-octadienyl, 1,8-nonadienyl, 1,9-decadienyl,1,11-dodecadienyl, p-di(eth-2-yl)benzene,bis-(4-(prop-3-yl)oxyphenyl)-sulphone,bis-(4-(prop-3-yl)oxyphenyl)-ketone,bis-(4-(prop-3-yl)oxyphenyl)-methane,1,1-bis-(4-(prop-3-yl)oxyphenyl)-ethane,2,2-bis-(4-(prop-3-yl)oxyphenyl)-propane,2,2-bis-(4-(prop-3-yl)oxyphenyl)-perfluoropropane,2,2-bis-(4-(prop-3-yl)oxy-3,5-dibromophenyl)-propane,3,3-bis-(4-(prop-3-yl)oxyphenyl)-pentane,4,4-bis-(4-(prop-3-yl)oxyphenyl)-heptane,1,1-bis-(4-(prop-3-yl)oxyphenyl)-cyclopentane,1,1-bis-(4-(prop-3-yl)oxyphenyl)-cyclohexane,1,1-bis-(4-(prop-3-yl)oxyphenyl)-3,3,5-trimethyl-cyclohexane,1,1,1-tris-(4-(prop-3-yl)oxyphenyl)-ethane,bis-((prop-3-yl-ether)oxy)-tricyclo[5.2.1.0^(2,6)]-decane;

[0019] E=A or a polymerizable group taken from the groupG—C[(Q—T—L)_(a)(A)_(3−a)] and/or Q—L and optionally also X—T—L, up to50%, preferably under 25% to 0% being permitted to correspond to thegroups E in an average molecule A, with the proviso that in the case ofmolecules with only one siloxane ring, under 25% to 0% is permitted tocorrespond to the groups E in an average molecule A, and with theproviso that at least one group G—C[(Q—T—L)_(a)(A)_(3−a)] and/or Q—Lmust be contained in the molecule;

[0020] G=linear, branched or cyclic C₁ to C₂₅, preferably C₁ to C₂₀alk(en)ylene, arylene, alkarylene, arylalkylene, 0 to 5 C atoms beingable to be replaced by a representative of the group O, S, N—A, C(O),C(O)O, OC(O), C(O)N, NC(O), OC(O)O, NC(O)O, OC(O)N, NC(O)N;

[0021] X=C₁ to C₁₀ alk(en)ylene, preferably ethylene, methylethylene,propylene, butylene, hexylene, ethenylene, propenylene;

[0022] Q=a radical containing an aromatic or polycyclic ring system inthe chain, with 5 to 20, preferably 6 to 15 C atoms, which independentlyof each other also has 0 to 5 heteroatoms from the group O, N—A, S inthe ring system;

[0023] T=O, N—A or a bi- or multivalent linear, branched or cyclicalcohol, amine or amino alcohol radical with 2 to 10 C atoms, preferablyethanediol diyl, 1,4,7-trioxaheptane-diyl, 1,4,7,10-tetraoxadecane-diyl,1,4,7,10,13-pentaoxatridecane-diyl, glycerol-triyl,trimethylolpropane-triyl, pentaerythritol-tetryl;

[0024] L=an acrylate or methacrylate group;

[0025] a=2, 3.

[0026] in which the following mean:

[0027] x≦2+y+2z;

[0028] y=0, 1, 2, 3, 4, 5, 6, 7, 8, preferably 0, 1, 2, 3;

[0029] z=0, 1, 2, 3, 4, 5, 6, 7, 8, preferably 0, 1, 2, 3;

[0030] A and D have the above meaning with the proviso that at least 3of the radicals D in a molecule must have the meaning ofG—C[(Q—T—L)_(a)(A)_(3−a)] or Q—L or X—T—L, and with the proviso thatwhere y=z=0, at least 1 radical D has the meaningG—C[(Q—T—L)_(a)(A)_(3−a)];

[0031] and the “*” symbols in (2.1) signify the connection points forfragments (2.2) via their valency symbolized by a “*” to the fragment(2.1).

[0032] Each selection of a radical named several times in the context ofthis application via indices or via the multiple naming of the symbol isto be considered independently of every other selection from the samegroup. For example, the triple naming of a radical A in a molecule canmean that the position A can be replaced by methyl and ethyl and propylin the same molecule.

[0033] Compounds according to formula (1) are based on cyclic siloxanes,one or more siloxane rings being able to occur per molecule.

[0034] Compounds according to formula (2) are based on linear orbranched siloxanes, one or more siloxane radicals being able to occurper molecule.

[0035] The preparation of compounds of the general formulae (1) and (2)takes place preferably by hydrosilylation. Si—H-functionalcyclosiloxanes and branched or linear siloxanes can thus be linked toC—C unsaturated organic structures (B. Marciniec: Comprehensive Handbookon Hydrosilylation, Pergamon Press, 1992). Desired monomer structures ofthe general formulae can be represented in this way.

[0036] Preferred Si—H-functional silicon core pieces for conversion torepresentatives of formulae (1) and (2) according to the invention areexemplary and include without limitation: D^(H) ₄, D^(H) ₅, D^(H) ₇,D^(H) ₈, a mixture of D^(H) _(x), with x=4, 5, 6, 7, 8, 9, 10 (sum ofthese components >90%), M^(H) ₂, M^(H) ₄Q, M^(H) ₃T, M^(H) ₃T^(H), M^(H)₃T^(Ph), M^(H) ₈Q₈, T^(H) ₈ (silicon nomenclature according toEncyclopedia of Polymer Science and Engineering 2^(nd) Ed. Vol. 15 p.206ff; H=hydrido-functionalized, Ph=phenyl).

[0037] For example, 1,3,5,7-tetramethylcyclotetrasiloxane in a solventsuch as toluene, under the influence of precious-metal catalysts such as(without limitation thereto) Speier catalysts, Karstedt catalysts butalso Wilkinson catalysts, can be linked to four mol vinylbenzylmethacrylate to a representative of (1). Instead of thecyclotetrasiloxane, a commercially available mixture of SiH-cycles(Petrarch, M8830) (a mixture of D^(H) _(x), with x=4, 5, 6) can also beused. Instead of vinylbenzyl methacrylate, other unsaturated compoundssuch as vinyinorbornenol methacrylate or allyl ethers, esters or amidesof (meth)acrylate-functional Bisphenol-A derivatives, as well asendocyclic unsaturated and other (meth)acryl-functional organicmolecules can be used. A further possibility according to the inventionis to react the cyclosiloxane component not only with aromatic orpolycyclic hydrosilylatable (meth)acrylates, but to do this in themixture with aliphatic hydrosilylatable (meth)acrylates such as forexample allyloxyethyl methacrylate or glycerol dimethacrylate allylether. However, products according to the invention are only theportions which carry at least one aromatic or polycyclic (meth)acrylatecomponent in the molecule.

[0038] In the case of the reaction of polyfunctional SiH-cyclosiloxaneswith likewise multiple C—C unsaturated organic structures (with theexception of the polymerizable double bonds), all C—C unsaturatedfunctions of the organic structure can be saturated with in each case acyclosiloxane ring through a suitable reaction procedure. However,pre-cross-linked intermediate products can also be produced by adifferent choice of stoichiometry or reaction procedure. Bothpossibilities can be used independently of each other.

[0039] The structures shown in the following can be obtained in per seknown manner by hydrosilylation of suitable Si—H compounds, for examplewith allyl or vinyl compounds. In the case of hydrosilylation, a mixtureof isomeric adducts are obtained in various proportions (α- andβ-adduct: see schema (I)) independently of the substrates and thecatalyst. In each case, only one isomer is shown in the formulae, butall possibilities are meant.

[0040] In addition to the methacrylates shown in the preferred examples,the corresponding acrylates as well as mixed types are also preferred.

[0041] Preferred representatives of formula (1) are:

[0042] m=4, 5 or a mixture of 4, 5 and 6 (i.e.: n=0, 1, 2); x=1 to m−1,Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; X=1,2-ethylene,T=1-oxa-1,3-propylene, L=methacrylate;

[0043] m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2);Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate;

[0044] m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2);Q=1,2-ethylene-(2-(4-methyleneoxyl-1,4(3)-phenylene); L=methacrylate;

[0045] m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2); A=methyl;D=E; G=1,4-butylene, a=2; Q=1,4-phenylene; T=1,2-ethanediol-diyl;L=methacrylate.

[0046] m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2); A=methyl;D=E; G=1,2-ethylene, a=2; Q=1,4-phenylene; T=1,2-ethanediol-diyl;L=methacrylate.

[0047] m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2); A=methyl;D=E; G=4,7-dioxa-8-oxo-1,10-decylene, a=2; Q=1,4-phenylene;T=1,2-ethanediol-diyl; L=methacrylate.

[0048] m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2); A=methyl;D=E; G=4-oxa-1,4-butylene-4-(1,4-phenylene); a=2; Q=1,4-phenylene;T=1,2-ethanediol-diyl; L=methacrylate.

[0049] m=4 (with n=0); A=methyl; D=E,bis-[2,2-propanediyl-(4-(1,3-propylene-oxy)-1-phenylene);Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate;

[0050] m=4 (with n=0); A=methyl; D=E,bis-[1,4-(1,2-ethanediyl)-phenylene);Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate;

[0051] m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2); A=methyl;D=E; Q=2(3)-oxyl-tricyclo[5.2.1.0^(2,6)]decane-6(7)-yl; L=methacrylate;

[0052] Preferred representatives of formula (2) are:

[0053] x=2; y=0; z=0; K=methyl, G—C[(Q—T—L)_(a)A_(3−a]; G=)1,4-butylene;A=methyl; a=2; Q=1,4-phenylene; T=1,2-ethanediol-diyl; L=methacrylate.

[0054] x=2; y=0; z=0; K=methyl, G—C[(Q—T—L)_(a)A_(3−a]; G=)1,2-ethylene;A=methyl; a=2; Q=1,4-phenylene; T=1,2-ethanediol-diyl; L=methacrylate.

[0055] x=2; y=0; z=0; K=methyl,G—C[(Q—T—L)_(a)A_(3−a]; G=)4,7-dioxa-8-oxo-1,10-decylene; A=methyl; a=2;Q=1,4-phenylene; T=1,2-ethanediol-diyl; L=methacrylate.

[0056] x=2; y=0; z=0; K=methyl,G—C[(Q—T—L)_(a)A_(3−a]; G=)4-oxa-1,4-butylene-4-(1,4-phenylene;A=methyl; a=2; Q=1,4-phenylene; T=1,2-ethanediol-diyl; L=methacrylate.

[0057] x=4; y=0; z=1; K=methyl, Q—L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate;

[0058] x=3; y=1; z=0; K=methyl, Q—L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate;

[0059] x=3; y=1; z=0; K=methyl, Q—L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate;

[0060] x=3; y=1; z=0; K=methyl, phenyl, Q—L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-1,2-(ethanediyl)-yl; L=methacrylate;

[0061] x=4; y=0; z=1; K=methyl, Q—L;Q=1,2-ethylene-(2-(4-methyleneoxyl-1,4(3)-phenylene); L=methacrylate;

[0062] x=4; y=0; z=1; K=methyl, 1,4-phenylene, Q—L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate;

[0063] x=2; y=0; z=0; K=methyl, Q—L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate;

[0064] x=2; y=0; z=0; K=methyl, Q—L;Q=1,2-ethylene-(2-(4-methyleneoxyl-1,4(3)-phenylene); L=methacrylate;

[0065] According to the invention, there can also be prepared from themonomers according to formulae (1) and/or (2) curable materialscontaining:

[0066] (K1) 0 to 70, preferably 0 to 20 wt.-% monomers according toformula (1),

[0067] (K2) 0 to 70, preferably 0 to 20 wt.-% monomers according toformula (2),

[0068] (K3) 0 to 50, preferably 3 to 20 wt.-% co-monomers,

[0069] (K4) 20 to 90, preferably 70 to 85 wt.-% fillers,

[0070] (K5) 0.001 to 5, preferably 0.1 to 2 wt.-% initiators,

[0071] (K6) 0 to 20, preferably 0 to 5 wt.-% auxiliaries,

[0072] with the proviso that the sum of the components (K1) and (K2) isat least 10 wt.-%, preferably at least 12 wt.-%.

[0073] Co-monomers according to component (K3) are at least singlyethylenically unsaturated. Preferably used ethylenically unsaturatedco-monomers are acrylates or methacrylates. Mono- and polyfunctional(meth)acrylate monomers are generally suitable. Typical representativesof this class of compounds (DE-A-43 28 960) are alkyl(meth)acrylates,including the cycloalkyl(meth)acrylates, aralkyl(meth)acrylates and2-hydroxyalkyl (meth)acrylates, for example hydroxypropyl methacrylate,hydroxyethyl methacrylate, isobornyl acrylate, isobornyl methacrylate,butyl glycol methacrylate, acetyl glycol methacrylate, triethyleneglycol dimethacrylate, polyethylene glycol dimethacrylate,2-phenyl-ethyl methacrylate, 2-ethylhexyl methacrylate, cyclohexylmethacrylate, lauryl methacrylate and hexanediol di(meth)acrylate.Long-chained monomers based on Bisphenol A and glycidyl methacrylate,which are known from U.S. Pat. No. 3,066,112, or their derivativesresulting from addition of isocyanates can also be used. Compounds ofthe Bisphenyl-A-diethyloxy(meth)acrylate andBisphenol-A-dipropyloxy(meth)acrylate type are also suitable. Theoligoethoxylated and oligopropoxylated Bisphenol-A diacrylic anddimethacrylic acid esters can also be used. The diacrylic anddimethacrylic acid esters ofbis(hydroxymethyl)-tricyclo[5.2.1.0^(2,6)]-decane named in DE-C-28 16823 and the diacrylic and dimethacrylic acid esters of the compounds ofbis(hydroxymethyl)-tricyclo[5.2.1.0^(2,6)]-decane extended with 1 to 3ethylene oxide and/or propylene oxide units are also well suited.

[0074] Inorganic fillers can as a rule be used as fillers according tocomponent (K4). Quartz, ground glasses, silica gels as well as pyrogenicsilicic acids and precipitation silicic acids or their granules can becited as examples. X-ray-opaque fillers are also preferably used, atleast partially. These can for example be X-ray-opaque glasses, i.e.glasses which for example contain strontium, barium or lanthanum (e.g.according to U.S. Pat. No. 3,971,754) or some of the fillers consist ofan X-ray-opaque additive, such as for example yttrium trifluoride,strontium hexafluorozirconate or fluorides of the rare earth metals(e.g. according to EP-A-0 238 025). For better incorporation into thepolymer matrix, it is advantageous to hydrophobize the inorganicfillers. Customary hydrophobization agents are silanes, for exampletrimethoxymethacryloyloxypropyl silane or trimethoxyglycidyl silane.

[0075] The fillers preferably have an average grain size <20 μm, inparticular <5 μm and an upper grain limit of 150 μm, preferably 70 μmand in particular 25 μm.

[0076] Mixtures of 5 to 25 wt.-% fillers with an average grain size of0.02 to 0.06 μm and 65 to 85 wt.-% fillers with an average grain size of1 to 5 μm are particularly preferably used.

[0077] Such systems which in a suitable period of time are able to formradicals are used as initiators according to component (K5). In the caseof single-component materials, photoinitiators which can trigger thepolymerization reaction through irradiation with UV or visible light areused for this.

[0078] Representatives of such photoinitiators are for example benzoinalkyl ethers, benzil ketals, acylphosphinic oxides or aliphatic andaromatic 1,2-diketone compounds, for example camphorquinone, the lightpolymerization being able to be accelerated by the addition ofactivators, such as tertiary amines or organic phosphites, in a mannerknown per se.

[0079] Suitable initiator systems for the triggering of thepolymerization via a redox mechanism are for example the peroxide/amineor peroxide/barbituric acid derivatives systems or similar. When usingsuch initiator systems, it is expedient to keep an initiator (e.g.peroxide) and a catalyst component (e.g. amine) ready separately. Thetwo components are then homogeneously mixed with each other shortlybefore they are used.

[0080] Suitable auxiliaries according to component (K6) can for examplenormally be stabilizers, pigments or thinning agents used in the fieldof dentistry.

[0081] The preparation process of the materials disclosed here ispreferably such that the liquid constituents are mixed with one another,the initiators, if they are not liquid, are introduced therein bystirring and the fillers are then added. A good homogenization can beachieved by kneading.

[0082] Two-component preparations which are cured by redox mechanismsare formulated such that the essential constituents of the redoxinitiation system are each introduced separately into a part of thetwo-component preparation. The distribution of the constituents of theoverall preparation is based on the relevant storage properties and thedesired mixing ratio.

[0083] The polymerizable materials are characterized by a highfilling-substance content and associated high strength withsimultaneously good processability.

[0084] The materials according to the invention are suitable inparticular as materials for dental purposes, for example for theproduction of artificial teeth or temporary fittings, as coatingproducts, for the gluing of substrates and as dental filling materials.

[0085] The materials according to the invention are usually introducedinto receptacles such as tubular bags, single- or multi-chamberedcartridges or capsules and other application units, for example blisterpacks or syringes, as known from the field of dentistry.

[0086] The invention is described in more detail in the following byexamples without being limited thereby.

EXAMPLES Preparation Example 1 Preparation of1,3,5,7-tetrakis[2(3)-methacryloyl-bicyclo[2.2.1]heptane-5-(1,3-propanediyl]-1,3,5,7-tetramethyl-cyclotetrasiloxane(1.1)

[0087] 10 g (41.6 mmol) 1,3,5,7-tetramethylcyclotetrasiloxane aredissolved in 50 ml of toluene and stirred with 34.3 g (166 mmol)5-vinyl-2(3)-norbornanyl-methacrylate (prepared according to U.S. Pat.No. 3,927,116) and with Karstedt catalyst (3 to 3.5% Pt, 200 ppm Pt,ABCR) for 24 hours. The reaction is checked by means of IR and, if anySi—H bands are still present at approximately 2100 cm⁻¹, subsequentlystirred until the bands disappear. After the customary working up andproduct isolation, 45.2 g (93%) of a bright-yellow viscous oil areobtained. Viscosity η (23° C.)=70 Pa*s, n_(D) ²⁰=1.496.

Preparation Example 2 Preparation of1,3,5,7-tetrakis[4(3)-methacryloylmethylene-phenyl-1-(1,2-ethanediyl]-1,3,5,7-tetramethyl-cyclotetrasiloxane(1.3)

[0088] 10 g (41.6 mmol) of 1,3,5,7-tetramethylcyclotetrasiloxane aredissolved in 50 ml toluene and stirred with 33.7 g (166 mmol)4(3)-vinylbenzyl-methacrylate (prepared according to Example 1 of EP-A-0381 005) and with Karstedt catalyst (3 to 3.5% Pt, 200 ppm Pt, ABCR) for24 hours. The reaction is checked by means of IR and, if any Si—H bandsare still present at approximately 2100 cm⁻¹, subsequently stirred untilthe bands disappear. After the customary working up and productisolation, 45.2 g (93%) of a bright-yellow viscous oil are obtained.Viscosity η (23° C.)=45 Pa*s, n_(D) ²⁰=1.528.

Preparation Example 3 Preparation of1,5-bis[2(3)-methacryloyl-bicyclo[2.2.1]heptane-5-(1,2-ethanediyl]-1,1,5,5-tetramethyl-3,3-bis-[2-(2(3)-methacryloyl-bicyclo[2.2.1]heptane-5-(1,2-ethanediyl)-2,2-dimethylsiloxy]-trisiloxane(2.5)

[0089] 10 g (30.4 mmol) tetrakis-dimethylsiloxy-silane are dissolved in50 ml toluene and stirred with 25.1 g (122 mmol)5-vinyl-2(3)-norbornanyl-methacrylate (prepared according to Example XIVof U.S. Pat. No. 3,927,116) and with Karstedt catalyst (3 to 3.5% Pt,200 ppm Pt, ABCR) for 24 hours. The reaction is checked by means of IRand, if any Si—H bands are still present at approximately 2100 cm⁻¹,subsequently stirred until the bands disappear. After the customaryworking up and product isolation, 45.2 g (93%) of a bright-yellowviscous oil are obtained. Viscosity η (23° C.)=12 Pa*s, n_(D) ²⁰=1.492.

Preparation Example 4 Preparation of1,4-bis[2-(1,3,5,7-tetramethyl-1,3,5,7-(2(3)-methacryloyl-bicyclo[2.2.1]heptane-5-(1,2-ethanediyl)-cyclotetrasiloxanyl)-1,2-ethanediyl]-benzene(1.8)

[0090] 625 g (2.6 mol) 1,3,5,7-tetramethyl-cyclotetrasiloxane areintroduced under reflux with 500 ml toluene and 0.8 g platinum on activecarbon. 169 g divinylbenzene (1.3 mol; 80%, technical, Aldrich) areadded to this. After the disappearance of the vinylic protons in the¹H-NMR, processing is carried out in the usual way. 587 g (92% of thetheoretical value) of a colourless oil with the viscosity η (23° C.)=0.3Pa*s and a refractive index of 1.471 are obtained.

[0091] 21.7 g (0.105 mol) 5-vinyl-2(3)-norbornanyl-methacrylate and 50ml toluene are reacted with Karstedt catalyst (3 to 3.5% Pt, 200 ppm Pt,ABCR). 11.3 g of the oil prepared in the previous paragraph are addeddropwise at 50° C. and the mixture stirred for 24 hours. The reaction ischecked by means of IR and, if any Si—H bands are still present atapproximately 2100 cm⁻¹, stirred until the bands disappear. After thecustomary working up and product isolation, 29.0 g (88%) of abright-yellow viscous oil are obtained. Viscosity η (23° C.)=78 Pa*s,n_(D) ²⁰=1.480.

Preparation Example 5 Reaction of a Mixture of SiH-Cycles with a Mixtureof Allyloxyethyl Methacrylate and 5-vinyl-2(3)-norbornanyl-methacrylate

[0092] 10 g (166 mmol based on SiH) of a mixture of SiH-cycles (40%D^(H) ₄, 45% D^(H) ₅, the rest higher rings) are dissolved in 50 mltoluene and stirred with a mixture of 17.2 g (84 mmol)5-vinyl-2(3)-norbornanyl-methacrylate (prepared according to U.S. Pat.No. 3,927,116), 14.3 g (84 mmol) allyloxyethyl methacrylate andhexachloroplatinic acid (dissolved in i-propanol) for 24 hours. Thereaction is checked by means of IR and, if any Si—H bands are stillpresent at approximately 2100 cm⁻¹, subsequently stirred until the bandsdisappear. After the customary working up and product isolation, 40 g(96%) of a bright-yellow viscous oil are obtained. Viscosity 2 Pa*s,n_(D) ²⁰=1.486.

Application Examples, Comparison Example

[0093] The pasty preparations according to the application examples andthe comparison example, the compositions of which are described in Table1, were prepared in a 100-ml laboratory kneader.

[0094] The preparations were characterized in accordance with DIN ISO4049 in respect of compression and bending strength.

[0095] The testpieces were prepared by irradiation of the materialsintroduced into moulds over a period of 40 seconds using the Elipar® IIlighting device of ESPE Dental AG, Germany.

[0096] Following removal from the mould, the testpieces were stored indeionized water at 36° C. for a period of 24 hours, after which themechanical properties were ascertained.

[0097] The volume shrinkage occurring during the radical polymerizationwas established by measuring the densities of the pasty preparations andof the cured compositions, using the Archimedes buoyancy method.

[0098] The opacity was measured by means of specimens with a definedheight of 3.5 (+/−0.05) mm. These are prepared by filling the materialto be checked into suitably high rings, evenly and free of bubbles, andilluminating it in the contact every 40 s by means of a lighting device(Elipar® II, ESPE) between plane, transparent matrices. The demouldedspecimens are then subsequently hardened under vacuum in a lightingdevice (Visio® beta, ESPE) for another 15 mins. The opacity is thenmeasured with the colour measuring device “HunterLab LabScanSpectralcolorimeter” of Hunter Lab Associates Laboratory, Inc., USA(Software SpecWare Software Version 1.10) and given by the device in%-values.

[0099] A summary of the property values ascertained for the curedpreparations according to the application examples or the comparisonexample is shown in Table 2. TABLE 1 Composition of the pastypreparations according to the application examples or the comparisonexample. Application Comparison Constituent example No. example No.(Proportions in wt.-%) A1 A2 A3 V1 V2 V3 (K1) Monomer according topreferred representative 1.1 22.5 10.3 11.3 (K1) Monomer according topreferred representative 1.8 10.3 (K1) Monomer according to preferredrepresentative 2.5 11.31,3,5,7-tetramethyl-1,3,5,7-tetrakis-(3-methacryloxypropyl)- 9.6 22.4cyclotetrasiloxane2,2-bis-4(3-hydroxypropoxyphenyl)propane-dimethacrylate 7.67,7,9-trimethyl-4, 13-dioxo-3, 14-dioxa-5, 12-diaza-hexadecane- 11.81,16-dioldimethacrylate Bis-acryloylmethyltricyclo[5.2.1.0^(2,6)]decane15.7 (K2) Sr silicate glass, average particle size 1.2 micrometers, 73.976.4 74.0 35.0 77.1 silanized (K2) Pyrogenic silicic acid 3.1 2.5 2.9(K2) Quartz powder, average particle size 1.5 micrometers, 41.2 78.1silanized (K5) 2,2′-(3-methoxypropylnitrilo)diethanoldimethacrylate 0.40.4 0.4 0.4 0.4 0.4 (K5) 1,7,7-trimethyl-bicyclo[2.2.1]heptane-2,3-dion0.07 0.07 0.07 0.06 0.07 0.07

[0100] TABLE 2 Composition of the property values, ascertained for thecured preparations according to the application examples or thecomparison example. Application example Comparison No. example No.Property A1 A2 A3 V1 V2 V3 Compression strength [MPa] 380 373 405 411416 345 Bending strength [MPa] 109 99 115 117 97 92 Elasticity modulus[MPa] 9678 8952 10025 8120 7348 4569 Volume shrinkage [%] 1.70 2.35 2.323.67 2.81 2.67 Opacity in [%] 84 80 80 82 96 98

[0101] The dental materials prepared using the monomers according to theinvention show an opacity of approximately 85%, which makes possible thevisual impression of natural tooth substance. The comparison examplesare either clearly more opaque, as a result of which the restorationmaterial has an unsatisfactory aesthetic appearance, or containlow-molecular monomers and therefore do not meet the toxicologicalrequirements.

[0102] Outstanding physical values with optimal opacity can be achievedwith the dental materials prepared from the high-molecular monomersaccording to the invention.

[0103] In particular the volume shrinkage is extremely low and thedental materials are therefore well suited for the permanent restorativecare of a patient.

1. Monomers according to the following formula:

in which the following mean: n=an integer from 0 to 10; A=H or linear orbranched C₁ to C₁₅ alk(en)yl, or C₃ to C₁₅ cycloalk(en)yl or C₆ to C₁₂aryl or C₈-C₁₈ alkaryl, of the named radicals, one or more C atoms ineach case being able to be replaced by O, C═O, O(C═O), SiR₂ and/or NR, Rbeing an aliphatic radical with 1 to 7 C atoms, in which one or more Catoms can be replaced by O, C═O and/or O(C═O); D=E or a hydrocarbonstructure which links 2 to 10, preferably 2 to 5 cyclosiloxane radicals,the structure being linear or branched or cyclic or polycyclic andcontaining 2 to 50 C atoms and additionally 0 to 30 other atoms from thegroup O, N, S, P, Cl, F, Br, I and to which 1 to 9 of the above-definedcyclosiloxane radicals according to formula (1), excluding D, areattached; E=A or a polymerizable group taken from the groupG—C[(Q—T—L)_(a)(A)_(3−a)] and/or Q—L and optionally also X—T—L, up to50%, preferably under 25% to 0% being permitted to correspond to thegroups E in an average molecule A, with the proviso that in the case ofmolecules with only one siloxane ring, under 25% to 0% is permitted tocorrespond to the groups E in an average molecule A, and with theproviso that at least one group G—C[(Q—T—L)_(a)(A)_(3−a)] and/or Q—Lmust be contained in the molecule; G=linear, branched or cyclic C₁ toC₂₅ alk(en)ylene, arylene, alkarylene, arylalkylene, 0 to 5 C atomsbeing able to be replaced by a representative of the group O, S, N—A,C(O), C(O)O, OC(O), C(O)N, NC(O), OC(O)O, NC(O)O, OC(O)N, NC(O)N; X=C₁to C₁₀ alk(en)ylene; Q=a radical containing an aromatic or polycyclicring system in the chain, with 5 to 20 C atoms, which independently ofeach other also has 0 to 5 heteroatoms from the group O, N—A, S in thering system; T=O, N—A or a bi- or multivalent linear, branched or cyclicalcohol, amine or amino alcohol radical with 2 to 10 C atoms; L=anacrylate or methacrylate group; a=2,
 3. 2. Monomers according to thefollowing formula:

in which the following mean: x≦2+y+2z; y=0, 1, 2, 3, 4, 5, 6, 7, 8; z=0,1, 2, 3, 4, 5, 6, 7, 8; and A, D have the meaning as indicated in claim1; with the proviso that at least three of the radicals D in a moleculemust have the meaning of G—C[(Q—T—L)_(a)(A)_(3−a)] or Q—L or X—T—L, andwith the proviso that where y=z=0, at least one radical D has themeaning of G—C[(Q—T—L)_(a)(A)_(3−a)].
 3. Use of the monomers accordingto one of the preceding claims for the preparation of curable materials.4. Compositions containing (K1) 0 to 70 monomers according to claim 1,(K2) 0 to 70 monomers according to claim 2, (K3) 0 to 50 co-monomers,(K4) 20 to 90 wt.-% fillers, (K5) 0.001 to 5 wt.-% initiators, (K6) 0 to20 auxiliaries, with the proviso that the sum of the components (K1) and(K2) is at least 10 wt.-%.
 5. Compositions according to claim 4 with anopacity of 80 to 90%.
 6. Use of the compositions according to one ofclaims 4 or 5 for the preparation of curable materials, in particular ofdental materials.
 7. Use of the monomers according to claim 1 and/or 2or of the compositions according to one of claims 4 or 5 for thepreparation of dental materials with an opacity which is suitable forguaranteeing the visual impression of natural tooth substance. 8.Receptacle containing at least one material including monomers accordingto one of claims 1 or
 2. 9. Receptacle containing at least onecomposition according to one of claims 4 or
 5. 10. Use of cyclic orlinear siloxanes containing at least one side chainG—C[(Q—T—L)_(a)(A)_(3−a)] and/or Q—L, as described in claim 1, for thepreparation of curable materials with an opacity of 80 to 90%.